/*
 * Copyright 2009 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package fr.onevu.gwt.uibinder.rebind;

import com.google.gwt.core.ext.UnableToCompleteException;
import com.google.gwt.core.ext.typeinfo.JClassType;
import com.google.gwt.core.ext.typeinfo.JMethod;
import com.google.gwt.core.ext.typeinfo.JType;
import com.google.gwt.core.ext.typeinfo.NotFoundException;
import com.google.gwt.core.ext.typeinfo.TypeOracle;
import com.google.gwt.dom.client.Element;
import com.google.gwt.user.client.ui.RenderablePanel;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;

import fr.onevu.gwt.uibinder.rebind.model.OwnerClass;
import fr.onevu.gwt.uibinder.rebind.model.OwnerField;

/**
 * Most of the implementation of {@link FieldWriter}. Subclasses are responsible
 * for {@link FieldWriter#getQualifiedSourceName()} and
 * {@link FieldWriter#getInstantiableType()}.
 */
public abstract class AbstractFieldWriter implements FieldWriter {
	protected static final String NO_DEFAULT_CTOR_ERROR = "%1$s has no default (zero args) constructor. To fix this, you can define"
			+ " a @UiFactory method on the UiBinder's owner, or annotate a constructor of %2$s with" + " @UiConstructor.";

	protected static int nextAttachVar;

	public static String getNextAttachVar() {
		return "attachRecord" + nextAttachVar++;
	}

	protected final FieldManager manager;
	protected final Set<FieldWriter> needs = new LinkedHashSet<FieldWriter>();
	protected final List<String> statements = new ArrayList<String>();
	protected final List<String> attachStatements = new ArrayList<String>();
	protected final List<String> detachStatements = new ArrayList<String>();

	protected final String name;
	protected String initializer;
	protected boolean written;
	protected int buildPrecedence;
	protected final MortalLogger logger;
	protected final FieldWriterType fieldType;
	protected String html;

	public AbstractFieldWriter(FieldManager manager, FieldWriterType fieldType, String name, MortalLogger logger) {
		if (name == null) {
			throw new RuntimeException("name cannot be null");
		}
		this.manager = manager;
		this.name = name;
		this.logger = logger;
		this.buildPrecedence = 1;
		this.fieldType = fieldType;
	}

	@Override
	public void addAttachStatement(String format, Object... args) {
		attachStatements.add(String.format(format, args));
	}

	@Override
	public void addDetachStatement(String format, Object... args) {
		detachStatements.add(String.format(format, args));
	}

	@Override
	public void addStatement(String format, Object... args) {
		statements.add(String.format(format, args));
	}

	@Override
	public int getBuildPrecedence() {
		return buildPrecedence;
	}

	@Override
	public FieldWriterType getFieldType() {
		return fieldType;
	}

	public String getHtml() {
		return html + ".asString()";
	}

	public String getInitializer() {
		return initializer;
	}

	@Override
	public String getName() {
		return name;
	}

	@Override
	public String getNextReference() {
		return manager.convertFieldToGetter(name);
	}

	public JType getReturnType(String[] path, MonitoredLogger logger) {
		if (!name.equals(path[0])) {
			throw new RuntimeException(this + " asked to evaluate another field's path: " + path[0]);
		}

		List<String> pathList = Arrays.asList(path).subList(1, path.length);
		return getReturnType(getAssignableType(), pathList, logger);
	}

	public String getSafeHtml() {
		return html;
	}

	public void needs(FieldWriter f) {
		needs.add(f);
	}

	@Override
	public void setBuildPrecedence(int precedence) {
		this.buildPrecedence = precedence;
	}

	public void setHtml(String html) {
		this.html = html;
	}

	public void setInitializer(String initializer) {
		this.initializer = initializer;
	}

	@Override
	public String toString() {
		return String.format("[%s %s = %s]", this.getClass().getName(), name, initializer);
	}

	public void write(IndentedWriter w) throws UnableToCompleteException {
		if (written) {
			return;
		}

		for (FieldWriter f : needs) {
			f.write(w);
		}

		if (initializer == null) {
			JClassType type = getInstantiableType();
			if (type != null) {
				if ((type.isInterface() == null) && (type.findConstructor(new JType[0]) == null)) {
					logger.die(NO_DEFAULT_CTOR_ERROR, type.getQualifiedSourceName(), type.getName());
				}
			}
		}

		if (null == initializer) {
			initializer = String.format("(%1$s) GWT.create(%1$s.class)", getQualifiedSourceName());
		}

		w.write("%s %s = %s;", getQualifiedSourceName(), name, initializer);

		this.written = true;
	}

	@Override
	public void writeFieldBuilder(IndentedWriter w, int getterCount, OwnerField ownerField) {
		if (getterCount > 1) {
			w.write("%s;  // more than one getter call detected. Type: %s, precedence: %s", FieldManager.getFieldBuilder(name), getFieldType(), getBuildPrecedence());
			return;
		}

		if (getterCount == 0 && ownerField != null) {
			w.write("%s;  // no getter call detected but must bind to ui:field. " + "Type: %s, precedence: %s", FieldManager.getFieldBuilder(name), getFieldType(),
					getBuildPrecedence());
		}
	}

	@Override
	public void writeFieldDefinition(IndentedWriter w, TypeOracle typeOracle, OwnerClass ownerClass, FieldWriter field, DesignTimeUtils designTime,
			int getterCount, boolean useLazyWidgetBuilders) throws UnableToCompleteException {
		OwnerField ownerField = ownerClass.getUiField(field.getName());

		JClassType renderablePanelType = typeOracle.findType(RenderablePanel.class.getName());
		boolean outputAttachDetachCallbacks = useLazyWidgetBuilders && getAssignableType() != null && getAssignableType().isAssignableTo(renderablePanelType);

		// Check initializer. Provided value takes precedence over initializer.
		if (ownerField != null && ownerField.isProvided()) {
			initializer = String.format("owner.%s", name);
		} else if (initializer == null) {
			JClassType type = getInstantiableType();
			if (type != null) {
				if ((type.isInterface() == null) && (type.findConstructor(new JType[0]) == null)) {
					logger.die(NO_DEFAULT_CTOR_ERROR, type.getQualifiedSourceName(), type.getName());
				}
			}
			initializer = generateInitilizerForField(typeOracle, ownerClass, field);
		}

		w.newline();
		w.write("/**");
		w.write(" * Getter for %s called %s times. Type: %s. Build precedence: %s.", name, getterCount, getFieldType(), getBuildPrecedence());
		w.write(" */");
		if (getterCount > 1) {
			w.write("private %1$s %2$s;", getQualifiedSourceName(), name);
		}

		w.write("private %s %s {", getQualifiedSourceName(), FieldManager.getFieldGetter(name));
		w.indent();
		w.write("return %s;", (getterCount > 1) ? name : FieldManager.getFieldBuilder(name));
		w.outdent();
		w.write("}");

		w.write("private %s %s {", getQualifiedSourceName(), FieldManager.getFieldBuilder(name));
		w.indent();

		w.write("// Creation section.");
		if (getterCount > 1) {
			w.write("%s = %s;", name, initializer);
		} else {
			w.write("final %s %s = %s;", getQualifiedSourceName(), name, initializer);
		}
		if (ownerField != null && ownerField.isProvided() && !designTime.isDesignTime()) {
			w.write("assert %1$s != null : \"UiField %1$s with 'provided = true' was null\";", name);
		}

		w.write("// Setup section.");
		for (String s : statements) {
			w.write(s);
		}

		String attachedVar = null;

		if (attachStatements.size() > 0) {
			w.newline();
			w.write("// Attach section.");
			if (outputAttachDetachCallbacks) {
				// TODO(rdcastro): This is too coupled with RenderablePanel.
				// Make this nicer.
				w.write("%s.wrapInitializationCallback = ", getName());
				w.indent();
				w.indent();
				w.write("new com.google.gwt.user.client.Command() {");
				w.outdent();
				w.write("@Override public void execute() {");
				w.indent();
			} else {
				attachedVar = getNextAttachVar();

				JClassType elementType = typeOracle.findType(Element.class.getName());

				String elementToAttach = getInstantiableType().isAssignableTo(elementType) ? name : name + ".getElement()";

				w.write("UiBinderUtil.TempAttachment %s = UiBinderUtil.attachToDom(%s);", attachedVar, elementToAttach);
			}

			for (String s : attachStatements) {
				w.write(s);
			}

			if (outputAttachDetachCallbacks) {
				w.outdent();
				w.write("}");
				w.outdent();
				w.write("};");
			}
		}

		w.newline();
		// If we forced an attach, we should always detach, regardless of whether
		// there are any detach statements.
		if (attachedVar != null) {
			w.write("// Detach section.");
			w.write("%s.detach();", attachedVar);
		}

		if (detachStatements.size() > 0) {
			if (outputAttachDetachCallbacks) {
				w.write("%s.detachedInitializationCallback = ", getName());
				w.indent();
				w.indent();
				w.write("new com.google.gwt.user.client.Command() {");
				w.outdent();
				w.write("@Override public void execute() {");
				w.indent();
			}

			for (String s : detachStatements) {
				w.write(s);
			}

			if (outputAttachDetachCallbacks) {
				w.outdent();
				w.write("}");
				w.outdent();
				w.write("};");
			}
		}

		if ((ownerField != null) && !ownerField.isProvided()) {
			w.newline();
			w.write("this.owner.%1$s = %1$s;", name);
		}

		w.newline();
		w.write("return %s;", name);
		w.outdent();
		w.write("}");
	}

	protected void addNullCheck(IndentedWriter w, FieldWriter field) {
		if (isInternal(field))
			return;

		w.write("if(%1$s != null) {", field.getName());
		w.indent();
	}

	protected void afterNullCheck(IndentedWriter w, FieldWriter field) {
		if (isInternal(field))
			return;

		w.outdent();
		w.write("}");
	}

	protected String generateInitilizerForField(TypeOracle typeOracle, OwnerClass ownerClass, FieldWriter field) {
		return String.format("(%1$s) GWT.create(%1$s.class)", getQualifiedSourceName());
	}

	protected boolean isInternal(FieldWriter field) {
		if (UiBinderWriter.CLIENT_BUNDLE_FIELD.equals(name))
			return true;

		// FIXME tests are too week: this detects fields without ui:field (the
		// generator has surely a list of all fields with info about the ui:field
		// value)
		if (name.startsWith("domId"))
			return true;
		// from fr.onevu.gwt.uibinder.rebind.UiBinderWriter 1086
		if (name.startsWith("f_"))
			return true;

		return false;
	}

	protected JMethod findMethod(JClassType type, String methodName) {
		// TODO Move this and getClassHierarchyBreadthFirst to JClassType
		for (JClassType nextType : UiBinderWriter.getClassHierarchyBreadthFirst(type)) {
			try {
				return nextType.getMethod(methodName, new JType[0]);
			} catch (NotFoundException e) {
				/* try parent */
			}
		}
		return null;
	}

	protected JType getReturnType(JType type, List<String> path, MonitoredLogger logger) {
		// TODO(rjrjr,bobv) This is derived from CssResourceGenerator.validateValue
		// We should find a way share code

		Iterator<String> i = path.iterator();
		while (i.hasNext()) {
			String pathElement = i.next();

			JClassType referenceType = type.isClassOrInterface();
			if (referenceType == null) {
				logger.error("Cannot resolve member " + pathElement + " on non-reference type " + type.getQualifiedSourceName());
				return null;
			}

			JMethod m = findMethod(referenceType, pathElement);
			if (m == null) {
				logger.error("Could not find no-arg method named " + pathElement + " in type " + type.getQualifiedSourceName());
				return null;
			}

			type = m.getReturnType();
		}
		return type;
	}
}
